// creates a new BloomFilter - access via BloomFilter.createOptimal(...)
private BloomFilter(
File f,
int buckets,
int hashFns,
boolean force,
int seekThreshold,
BucketSize countBits,
Allocator cacheAllocator,
CloseCallback callback)
throws IOException {
this.closeCallback = callback;
this.seekThreshold = seekThreshold;
this.metadata = BloomMetadata.createNew(buckets, hashFns, countBits);
hash = new RepeatedMurmurHash(hashFns, this.metadata.getBucketCount());
// creating a new filter - so I can just be lazy and start it zero'd
cache = cacheAllocator.apply(this.metadata.getTotalLength() - this.metadata.getHeaderLength());
cacheDirty = true;
open = true;
if (f != null) {
if (f.exists()) {
if (force) {
if (!f.delete()) {
throw new IOException("Couldn't delete old file at " + f.getAbsolutePath());
}
} else {
throw new IllegalArgumentException(
"Can't create a new BloomFilter at "
+ f.getAbsolutePath()
+ " since it already exists");
}
}
file = new RandomAccessFile(f, "rw");
this.metadata.writeToFile(file);
file.setLength(metadata.getTotalLength());
file.getFD().sync();
unflushedChanges = new ConcurrentSkipListMap<Integer, Byte>();
if (f.length() != metadata.getTotalLength()) {
throw new RuntimeException(
"Bad size - expected " + metadata.getTotalLength() + " but got " + f.length());
}
} else {
unflushedChanges =
null; // don't bother keeping track of unflushed changes if this is memory only
file = null;
}
}
// Opens an existing bloom filter. Access via BloomFilter.openExisting(...)
private BloomFilter(
File f, int seekThreshold, Allocator cacheAllocator, CloseCallback closeCallback)
throws IOException {
assert f.exists() && f.isFile() && f.canRead() && f.canWrite()
: "Trying to open a non-existent bloom filter";
this.seekThreshold = seekThreshold;
this.closeCallback = closeCallback;
file = new RandomAccessFile(f, "rw");
this.metadata = BloomMetadata.readHeader(file);
unflushedChanges = new ConcurrentSkipListMap<Integer, Byte>();
// load the cache with the on disk data
cache = cacheAllocator.apply(metadata.getTotalLength() - metadata.getHeaderLength());
int readRes = file.read(cache);
assert readRes == (metadata.getTotalLength() - metadata.getHeaderLength())
: "I only read "
+ readRes
+ " bytes, but was expecting "
+ (metadata.getTotalLength() - metadata.getHeaderLength());
hash = new RepeatedMurmurHash(metadata.getHashFns(), metadata.getBucketCount());
open = true;
}
